Device for sensing and controlling the delivery pile of sheet-fed printing press

ABSTRACT

A device for sensing and controlling the height of a pile of sheets on the delivery table of a sheet-fed rotary printing press has a contactless sensing head loosely mounted on an oscillating shaft which carries the joggers for aligning the delivered sheets. The sensing head is resiliently urged against stop means to maintain it in sensing position but can be swung clear of the pile with the joggers when the shaft is rotated to bring the joggers away from the pile to take a proof sheet by the interengagement of dogs on the sensing head and the shaft. Switch means in the head are provided to stop the pile table motor when the head is swung clear.

United States Patent Abendroth et al.

[54] DEVICE FOR SENSING AND CONTROLLING THE DELIVERY PILE OF SHEET-FED PRINTING PRESS Inventors: Paul Abendroth, Offenbach am Main; Werner Kaiser, Offenbach am Main-Rumpenheim, Germany Roland Offselmaschinenfabrik Faber and Schleicher AG, Offenbach am Main, Germany Filed: Sept. 30, 1970 Appl. No.: 76,857

Assignee:

US. Cl ..271/88, 271/89 Int. Cl. ..B65h 31/38 Field of Search ..271/88, 89

References Cited UNITED STATES PATENTS 2,698,176 12/1954 Matthews ..271/89 [451 Nov.21,l972

11/1961 Blaha ..271/88 8/1968 Dobsonetal ..271/88 [5 7] ABSTRACT A device for sensing and controlling the height of a pile of sheets on the delivery table of a sheet-fed rotary printing press has a contactless sensing head loosely mounted on an oscillating shaft which carries the joggers for aligning, the delivered sheets. The sensing head is resiliently urged against stop means to maintain it in sensing position but can be swung clear of the pile with the joggers when the shaft is rotated to bring the joggers away from the pile to take a proof sheet by the interengagement of dogs on the sensing head and the shaft. Switch means in the head are provided to stop the pile table motor when the head is swung clear.

9 Claims, 5 Drawing Figures PATENTEDunv 21 m2 sum 2 or 2 FIG. 5

DEVICE FOR SENSING AND CONTROLLING THE DELIVERY PILE OF SHEET-FED PRINTING PRESS The invention relates to a device for sensing and controlling the height of a pile of sheets on the sheet delivery table of a sheet-fed rotary press, wherein the pile of sheets is aligned by periodically reciprocated joggers acting on the leading edge of the sheets.

Such devices are necessary in order to maintain constant the difference in height between the plane in which the sheets are conveyed to the delivery table by means of suitable conveyor devices, and the plane to which the sheets drop after release by the conveyor device. Joggers acting on the leading edges of the sheets are particularly suitable for the straightening of the pile.

It is generally known to use periodically displaced,

mechanical feelers for sensing and controlling a pile being stacked. Mechanical feelers have proved disadvantageous, however, particularly in modern highspeed machines, because they have to be constantly moved into the path of the sheets being delivered, in order to sense the height of the pile, and in the course of this they may easily touch and damage sheets. It should be borne in mind that, in this respect, the conditions at the delivery table are different from those at the feeder.

In a device disclosed in German Pat. specification No. 1,052,415, a mechanical pile feeler is hingedly connected to a jogger so that it is displaced in time with the jogger. Since the joggers are mounted at the side of the pile of sheets, they have to be adjustable to different sizes of sheets.

From German Pat. specification No. 1,175,699, a mechanical sensing device is known which is likewise controlled rhythmically and which can be pivoted by means of its own drive.

It is the object of the present invention to sense the height of the pile of sheets on the delivery table of a sheet-fed machine by means of a sensing head which is reliable in operation, and to select the position and manner of mounting this sensing head in such a manner that no further adjustments of the sensing head, interfering with continuous operation of the machine, are necessary, for example on a change of sheet sizes, before a pile is removed or when a sheet to be checked is extracted.

According to the invention, at least one sensing head is mounted loose on a periodically reciprocated holder for the front joggers and is held at rest until the holder has swung through a certain angle, and that on swivelling beyond this angle of swing, a dog secured to the holder also swivels the sensing head. It is an advantage to allow joggers and sensing head to act on the front edge of the delivery pile because the position of the front edge of the pile is retained even in the event of changes in sheet sizes. The joggers are preferably adapted for swivelling and possibly for removal so as not to interfere with sampling sheets or removal of the full pile. When the joggers and the sensing heads are mounted on the same holder, the swivelling and possible removal of this holder is sufficient, as a result of which the constructional expenditure is considerably reduced. In this case, however, it is essential to ensure that the sensing heads do not participate in the periodic swivelling of the joggers but remain at rest. Particularly with contactless sensing heads, particularly those capacitively operating, variations in the distance of the sensing member from the pile must be avoided during the sensing operation in order to prevent faulty control. The dog or catch acts only at relatively great angles of swing.

In one construction according to the invention, the sensing head is mounted loosely on a periodically reciprocated shaft, which is provided with the joggers, and is swung constantly, by spring force, against a fixed stop which is provided on a connecting member which, on the one hand is mounted loose on the shaft and on the other hand is pinned to a rigid shaft so that both shafts, including the joggers and the sensing head, can be dismounted from the machine as a single part. As a result of this arrangement, the effect is achieved that,

during machine operation, that is to say when the joggers are constantly reciprocating, the sensing head remains at rest and at the correct distance, which may be adjustable, from the pile of sheets. Nevertheless, the sensing head can be swung away and the whole assembly, which is stable as a result of the connecting members, can be dismounted easily and quickly as a whole.

A specific embodiment of the invention is characterized by a shoulder rigidly connected to the shaft, and a spring which is mounted between shoulder and sensing head and which swings the sensing head towards the pile of sheets until it comes into abutment while, on predetermined pivoting of the shaft in the opposite direction, the dog secured to the shaft impinges on a corresponding projection on the sensing headand moves this away from its stop against the force of the spring. This construction is particularly simple and stable.

Also in an embodiment of the invention, the positions of the stop and of the dog on the shaft are adjusta ble. Thus there is the possibility, on the one hand of varying the distance of the sensing head from the pile and on the other hand of varying the angle of swing at which the dog engages the sensing head.

The sensing head can be used both to limit the final height during the upward travel of the pile and also to regulate the height of the pile when the printing press is in operation. This double function of the sensing head is possible after care has been taken to ensure that the sensing head is always at the correct distance from the pile at the moment of sensing. Particularly with sensing head operating capacitively, the stop signal remains absent if the sensing head is swung even slightly out of position. If the sensing head were rigidly connected to the reciprocating holder for the joggers, however, then it would be possible, for example, with the machine stopped, that is to say with the joggers stationary, for the sensing head just to be in a position swung away from the pile and therefore to be unable to fulfil its function.

Preferably, when the sensing head is swung away from the pile of sheets, a switching element is actuated which switches off the pile table motor. This prevents the pile table motor from being actuated when the sensing head is swung away. The switching element may be a mechanically actuated microswitch or a mercury switch which operates at a specific inclination of the sensing head.

In order to improve the operational reliability, according to the invention, the sensing head is connected by means of a flexible electrical connection to the control circuit for the pile table motor which cannot be actuated when this connection is broken. As a result of this circuit, it is impossible to actuate the pile table motor when the sensing head is dismounted or not connected up.

One example of an embodiment of the invention is i].- lustrated diagrammatically in the accompanying drawings in which FIG. 1 slows a sheet-fed printing press with feeder and delivery elevator and a device for sensing the delivery pile;

FIG. 2 shows the sensing device of FIG. 1 greatly enlarged and seen from the side;

FIG. 3 shows a front view of the sensing device of FIG. 2;

FIG. 4 shows the sensing device taken on-the line IV-IV in FIG. 3, drawn partially in section; and

FIG. 5 shows diagrammatically the assembly for lifting and lowering the pile table.

The printing press 1 shown in FIG. 1 contains a sheet feeder 2, a plurality of printing-unit cylinders 3, a damping unit 4 and an inking unit 5, in conventional manner. The sheets emerging from the printing unit are grasped by sheet conveying devices 7 secured to endless chains 6, and are delivered from the machine upon the delivery pile 8. A pile sensing device 9 is mounted at the front edge of the delivery pile 8. The sheets forming the pile are stacked on a table 8a which is suspended from chains 10 and is displaced upwards and downwards by means of a pile table motor 43 as will be more fully described hereinafter.

A pile height sensing device shown as a touchless or contactless and preferably capacitatively operating sensing head 11, is mounted, as shown in FIGS. 2 to 4, for rotation on a shaft 12, which swings or oscillates backwards and forwards in time with the delivered sheets, in known manner, and to which there are pinned joggers fingers 13. The sensing head 11 is urged, by a spring 14, against a stationary stop 15 (see FIG. 4) which is adjustably secured to a connecting member 17 which is mounted for rotation on the shaft 12 but pinned to a stationary shaft 16. The spring 14 bears against a shoulder 18 on a ring 19 pinned to the shaft 12 on the one hand and against a projection 20 5O machined out of the sensing head 11 as a spring guide on the other hand. It is obvious that the shoulder 18 with the shaft 12 can be pivoted within a small angle without the bevelled face of the projection 20 on the sensing head 11 becoming detached from the stop 15, as shown in FIG. 4. A further ring 22 with a dog 23 is secured to the shaft 12. In the event of a large pivot angle of the joggers 13 or of the shaft 12 in a direction away from the pile 8, this dog engages with a corresponding projection 24 on the sensing head 11. Thus both joggers l3 and sensing head 11 can be swung away jointly by means of the handle 25 pinned to the shaft 12, so as to be able to take a proof sheet from the pile 8. In this case, a mercury switch 26 built into the sensing head 11 reaches its cut off angle and stops the pilemotor so thatup or down movement of the pile 8 is impossible with the sensing head 11 swung away.

Referring now to FIG. 5, this figure shows the pile table 80 to which the sheets forming pile 8 are delivered. The table is suitably coupled to chains 10 which are driven for lifting or lowering the pile table by motor 43.

Sensing head 11 which is rotatably'mounted on shaft 12, is arranged as already described, parallel to the front edge of the pile. As it is indicated by an angle, the sensing head can be swung out of its sensing position (illustrated position) into a position clear of the pile. The sensing head is connected via a flexible cord 40 including a plug connector 41 to a control unit of conventional design. Switch 26 which, as already stated, is preferably a mercury switch, is also connected to control unit 45. Unit 45 controls a relay 42 which opens thereby interrupting the energizing circuit of themotor thereby stopping the same when either plug connector 41 is separated or switch 26 is tilted into its opening position by swinging the sensing head clear of the pile.

Relay 44 also connected to unit 45 and included in the motor circuit, opens when sensing head 11 senses a height of the pile above a selected maximum level.

Only one jogger 13 and two connecting members 17 are illustrated in the drawing. It is obvious, however, that a plurality of these joggers and connecting members is provided over the width of the machine. It is further obvious that the shaft 12, including the parts secured thereto, and the shaft 16 can be dismounted from the machine as one part, for example when the pile 8 is to be removed but is so high that it would strike against joggers and sensing head. If the sensing head 1 l is also electrically disconnected from the machine during this dismounting, then the pile table motor is locked at the same time as described. The height of the sensing head 11 can be adjusted by turning the setscrew 27. After the screw 28 (FIG. 3) has been loosened, the ring 22 can be turned on the shaft 12 and so the idle motion of the dog 23 before engaging the projection 24 can be altered. Upon of loosening the nut 29 and turning the setscrew 30, the bevelled face of the stop 15 can be displaced and hence the position in which the sensing head bears against the stop 15.

What is claimed is:

l. A device for sensing and controlling the height of a pile of sheets delivered to an up and down movable pile table of a sheet-fed rotary printing press, said device comprising in combination:

a pile delivery table;

drive means for lifting and lowering said table,

conveying means for delivering sheets one by one and at a constant level to said table;

a support shaft for sheets joggers oscillating about its axis through a predetermined angle and mounted at a front edge of said table;

at least one sheet jogger fixedly seated on said shaft for oscillation in unison therewith;

pile height sensing means rotatably seated on said shaft;

releasable locking means holding said sensing means stationary relative to the shaft when and while said shaft oscillates within said predetermined angle, said locking means being releasable by turning the shaft through an angle greater than said oscillating angle;

releasable coupling means on the sensing means and the shaft for coupling the sensing means to the shaft for turning the sensing means in unison with the shaft, said coupling means being uncoupled where and while the sensing means is held stationary and coupled for turning the sensing means in unison with the shaft by pivoting the shaft through an angle greater than said predetermined oscillation angle.

2. The device according to claim 1 where said releasable locking means comprise a stop member, a nose member secured to the sensing means and spring means biasing said nose member into engagement with the stop member thereby retaining the sensing means in a predetermined stationary position relative to the shaft, said stop member and nose member being so correlated that the members remain in engagement when and while the shaft is oscillating through said oscillation angle but being disengaged upon turning the shaft past said angle thereby freeing the sensing means for coupling the same to the shaft by operation of the coupling means.

3. The device according to claim 2 wherein said stop member is mounted on a support member loosely seated on the shaft and fixedly secured to a second shaft, said shafts, said jogger and said sensing means constituting a structural unit detachable as a unit.

4. The device according to claim 3 wherein said coupling means comprise a catch member secured to said first shaft for rotation in unison therewith and a coacting abutment member fixedly secured to said sensing means in circumferential alignment with the catch member, the circumferential spacing of said members being such that said first shaft can freely oscillate within said predetermined angle but causes said members to become engaged when turned through an angle greater than the circumferential spacing of said members. a

5. The device according to claim 4 wherein-said stop member and said catch member are mounted for independently varying their operational positions.

6. The device according to claim 1 wherein said drive means for lifting and lowering the pile table comprises an electric motor connected to an energizing circuit including a switch means,'said switch means being closed when the sensing means is held stationary relative to the shaft by said locking means and opening saidcircuit when the sensing means is turned in unison with the shaft thereby stopping the motor. v

7. The device according to claim 6 wherein said switch means comprisesa mercury switch mounted to be closed in the stationary position of the sensing means relative to the shaft and to open upon turning of said sensing means out of said stationary position.

8. The device according to claim 6 wherein said sensing means are included in the energizing circuit of the motor via a separable connector means, separation of said connector means disconnecting said energizing circuit from the motor.

9. The device according to claim 1 wherein said sensing means is arranged to limit during lifting of the table the height of the pile to a predetermined maximal height and also to limit the height of the pile during delivery of sheets to the table. 

1. A device for sensing and controlling the height of a pile of sheets delivered to an up and down movable pile table of a sheetfed rotary printing press, said device comprising in combination: a pile delivery table; drive means for lifting and lowering said table; conveying means for delivering sheets one by one and at a constant level to said table; a support shaft for sheets joggers oscillating about its axis through a predetermined angle and mounted at a front edge of said table; at least one sheet jogger fixedly seated on said shaft for oscillation in unison therewith; pile height sensing means rotatably seated on said shaft; releasable locking means holding said sensing means stationary relative to the shaft when and while said shaft oscillates within said predetermined angle, said locking means being releasable by turning the shaft through an angle greater than said oscillating angle; releasable coupling means on the sensing means and the shaft for coupling the sensing means to the shaft for turning the sensing means in unison with the shaft, said coupling means being uncoupled where and while the sensing means is held stationary and coupled for turning the sensing means in unison with the shaft by pivoting the shaft through an angle greater than said predetermined oscillation angle.
 1. A device for sensing and controlling the height of a pile of sheets delivered to an up and down movable pile table of a sheet-fed rotary printing press, said device comprising in combination: a pile delivery table; drive means for lifting and lowering said table; conveying means for delivering sheets one by one and at a constant level to said table; a support shaft for sheets joggers oscillating about its axis through a predetermined angle and mounted at a front edge of said table; at least one sheet jogger fixedly seated on said shaft for oscillation in unison therewith; pile height sensing means rotatably seated on said shaft; releasable locking means holding said sensing means stationary relative to the shaft when and while said shaft oscillates within said predetermined angle, said locking means being releasable by turning the shaft through an angle greater than said oscillating angle; releasable coupling means on the sensing means and the shaft for coupling the sensing means to the shaft for turning the sensing means in unison with the shaft, said coupling means being uncoupled where and while the sensing means is held stationary and coupled for turning the sensing means in unison with the shaft by pivoting the shaft through an angle greater than said predetermined oscillation angle.
 2. The device according to claim 1 where said releasable locking means comprise a stop member, a nose member secured to the sensing means and spring means biasing said nose member into engagement with the stop member thereby retaining the sensing means in a predetermined stationary position relative to the shaft, said stop member and nose member being so correlated that the members remain in engagement when and while the shaft is oscillating through said oscillation angle but being disengaged upon turning the shaft past said angle thereby freeing the sensing means for coupling the same to the shaft by operation of the coupling means.
 3. The device according to claim 2 wherein said stop member is mounted on a support member loosely seated on the shaft and fixedly secured to a second shaft, said shafts, said jogger and said sensing means constituting a structural unit detachable as a unit.
 4. The device according to claim 3 wherein said coupling means comprise a catch member secured to said first shaft for rotation in unison therewith and a coacting abutment member fixedly secured to said sensing means in circumferential alignment with the catch member, the circumferential spacing of said members being such that said first shaft can freely oscillate within said predeterminEd angle but causes said members to become engaged when turned through an angle greater than the circumferential spacing of said members.
 5. The device according to claim 4 wherein said stop member and said catch member are mounted for independently varying their operational positions.
 6. The device according to claim 1 wherein said drive means for lifting and lowering the pile table comprises an electric motor connected to an energizing circuit including a switch means, said switch means being closed when the sensing means is held stationary relative to the shaft by said locking means and opening said circuit when the sensing means is turned in unison with the shaft thereby stopping the motor.
 7. The device according to claim 6 wherein said switch means comprises a mercury switch mounted to be closed in the stationary position of the sensing means relative to the shaft and to open upon turning of said sensing means out of said stationary position.
 8. The device according to claim 6 wherein said sensing means are included in the energizing circuit of the motor via a separable connector means, separation of said connector means disconnecting said energizing circuit from the motor. 